As part of building a my first station suitable for “tail-gate” or vehicle-based POTA activations, the consideration of which antenna provided the greatest flexibility led me to consider the JPC-12, which I acquired from DX Canada.
The antenna is quite compact and fits into the provided carry bag that is 35cm long and 24 cm high. In the bag are included a base, ground spike and mid-antenna coil, four antenna sections and a telescopic whip for the top of the antenna, see photos below.
Also included in the antenna bag was a ribbon cable counterpoise that attached at the top of the ground spike which screws into the antenna base with the coax connection. Not included in the bag was a mag mount base assembled from some general purpose magnets available from Princess Auto . The magnets included 1 x 95lbs strength magnet for the antenna base and 2 x 45lbs magnets for guy lines. Intended for static mobile set-up, remain untested.
Initial set-up was easy, although the whip part of the antenna is a little flimsy and the third section for the top became disconnected from the rest upon first use and required some clear hockey tape to be held in place. For field use I may acquire an additional 2.5M telescopic whip as it appears to be easily damaged. Also it is important to know that the bolt connections are all M10 x 1.5 metric and not 3/8 x 24 as you might expect. As such the antenna won’t work with existing tri-pods or other mounts using 3/8 x 24 bolts without an adapter. For the home-made mag mount I acquired an M10 x 1.5 tap and drill to fit a 30mm M10 bolt into the general purpose magnet. The use of a 5m 10-wire ribbon cable for the ground spike counterpoise was innovative although, as you can tell from the photo easily tangled when the wires were separated into five separate 5m 2-wire counterpoise branches. I acquired two additional 15 foot lengths of 10-wire ribbon cable to either extend the current counterpoise or add additional radials, more experimentation for future along with use of a mag mount.
Tuning this antenna required different combinations of parts and it is advised that an antenna analyzer would help with fine tuning. There are several YouTube videos on tuning this antenna and the table on the next page reflects tuning suggestions which I was generally able to replicate.
Other than testing in my yard with my NanoVNA, I have yet to try the JPC-12 at a park and look forward to doing so - maybe with a back-up wire antenna handy should any additional challenges come about!
73, Alan VA3IAH